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关于聚醚型非离子表面活性剂分子量的测定方法主要有用对甲苯磺酸及4-N,N二甲氨基吡啶或N-甲基咪唑为乙酰化催化剂测定聚醚多元醇的羟基数(即羟值法),用蒸气压渗透(VPO)法测定数均分子量,以及用凝胶渗透色谱(GPC)法进行分子量分级测定等。70年代以来,已开始将红外光谱、核磁共振谱、高效液相色谱及质谱等方法用于非离子表面活性剂的平均分子量测定。由于羟值法简便、快速和仪器简单,在工业生产中一直沿用为聚醚分子量测定的常规分析方法。但由于羟值法与VPO法的理论基础不同,两法所测分子量往往有一定差别。为此我们用羟值法对不同分子量的聚乙二醇(PEG)标样及本实验室合成的各种聚环氧乙烷无规聚醚进行分子量测定,并与VPO法对照,考察两方法的差别及羟值法的适用范围。
About polyether nonionic surfactant molecular weight determination method mainly p-toluenesulfonic acid and 4-N, N-dimethylaminopyridine or N-methylimidazole acetylation catalyst for the determination of the hydroxyl number of the polyether polyol (ie, hydroxyl Value method), vapor pressure penetration (VPO) method to determine the number average molecular weight, and gel permeation chromatography (GPC) molecular weight determination. Since the 1970s, infrared spectroscopy, nuclear magnetic resonance spectroscopy, high performance liquid chromatography and mass spectrometry and other methods have been used for the determination of the average molecular weight of non-ionic surfactants. Due to the simplicity, speed and simplicity of the hydroxyl value method, conventional analytical methods for the determination of polyether molecular weights have been used in industrial production. However, due to the difference between the theoretical basis of the hydroxyl value method and the VPO method, the molecular weights measured by the two methods often have some differences. To this end, we use hydroxyl value method for polyethylene glycol (PEG) standards of different molecular weights and various polyethylene oxide random polyether synthesized in our laboratory molecular weight determination, and with the VPO method, examine the two methods The difference and the scope of application of hydroxyl value method.